1. Field of the Invention
This invention relates to a remote dictation system. More particularly, it relates to improvements in dictation systems of the type that use ordinary telephones to dictate into a remote central recording unit (also called a host unit) and to retrieve recorded material therefrom.
The systems to which this invention relates are particularly useful in medical applications. A radiologist, for example, may dictate his observations to a central recording unit by means of a conventional telephone handset while viewing an X-ray photograph of a patient. A referring physician can later access the recorded report from another site, again by means of a telephone located at that site. The DTMF push-buttons on the telephones are used to transmit digits that identify the recordings and the physicians. The buttons also provide signals that control the usual voice recording functions such as record, playback, and rewind.
2. Brief Summary of the Invention
The principal object of the present invention is to enhance the ease of use of these recording systems. A more specific object is to facilitate the generation of control signals by the user. Another object is to make it easier for the user to deal with central recording units having different control protocols. A further object is to enable the central recording unit to detect the end of a recording or playback session as soon as the user has terminated it.
The invention is embodied primarily in a control unit connected to the user's telephone. An auxiliary keypad in the form of a thin, membrane-type switch unit adheres to the back of the user's handset at the receiver end thereof. A conductor pair from this switch extends to a substitute coil cord that replaces the coil cord originally connected between the handset and the telephone's base unit. The other end of this substitute cord plugs into the control unit, as does a line extending from the telephone base unit receptacle that ordinarily connects to the handset. Another line extends from the control unit to the telephone base unit jack that ordinarily connects to the telephone line. The telephone line, in turn, plugs into a receptacle in the control unit. The invention can be connected to a telephone without violating the integrity of the telephone because all the connections use existing quick-disconnect-type jacks in the telephone base and handset.
The control unit connects the voice wires from the handset directly to the corresponding connector in the telephone base unit. It also connects the telephone base unit to the telephone line, but by way of a "line sense and disconnect unit" that controls connection of the control unit and the telephone base unit to the telephone line.
In the preferred embodiment of the invention, the control unit has three modes of operation, selectable by means of a front panel switch. In an off mode, the telephone operates as a conventional telephone, with the telephone base unit connected to the telephone line. In a session mode, used for dictation to, and playback from, the host recording unit, the control unit activates the auxiliary keypad attached to the telephone handset and the control unit transmits, over the telephone line, tone signal(s) indicative of the respective buttons therein actuated by the user. Each tone signal is a DTMF signal that could otherwise be generated by a telephone in response to a user pressing a button on the telephone's dial. The control unit sends one or more tone signals in response to the user pressing a button on the auxiliary keypad. The tone signal(s) sent by the invention simulate to a central recording unit a user pressing a series of buttons on the telephone dial. Hereinafter, the "value" of an auxiliary keypad button is the series of button presses on a telephone dial that the invention simulates after a user presses, releases, or "clicks" (momentarily presses then releases) the button on the auxiliary keypad.
A third mode is a program mode in which the user can select the various functions that are activated by actuation of the respective buttons on the auxiliary keypad, i.e. the user can change the "value" of the buttons on the auxiliary keypad. The control unit prompts the user by generating voice messages and injecting them into the line to the telephone base unit. In this mode, the telephone and control unit are disconnected from the telephone line.
The line sense and disconnect unit serves an important function relating to release of telephone lines by the central recording unit. A user terminates a session with the central recording unit by going on-hook. In prior systems, the central recording unit would determine that a user has gone on-hook by waiting a predetermined length of time during which no signals are received from the user. This length of time has to be fairly substantial in order to prevent the central recording unit from disconnecting a user who has merely paused longer than usual in recording a message or in transmitting control signals to the central recording unit. This unduly ties up central recording unit ports and telephone lines at the central recording unit. In accordance with the present invention, the line sense and disconnect unit senses an on-hook condition in the telephone base unit, indicating the user has terminated a session, and then holds the telephone line and transmits a termination signal to the central recording unit before dropping the line. The central recording unit, in turn, holds the connection at its end until it receives a termination signal. In this way, the central recording unit can disconnect immediately upon termination of a session, without prematurely disconnecting because of a pause in a transmission by the user.